Frequently asked questions
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Q: Can I run mono to eight-layer films on a nine-layer line?
A: Yes, Our customers who own nine-layer lines do run mono to eight-layer films if need be.
Q: I'm wondering if I should add more layers to my coextrusion line. What should I do?
A: This is highly application dependent as some markets do not require complex film structures. Contact us for a discussion on why more layers would be appropriate, and to do a mechanical and process feasibility analysis on your current line. Feasibility of adding more layers is not an issue with our scalable SCD® technology, but it will be if a die was purchased elsewhere. Additional layers will also add more extrusion capacity, so a check into the process limits needs to be conducted.
Q: I'm wondering if my line is outputting the same value as it was when first purchased. How do I check that?
A: A common maintenance item to be periodically checked is feedscrew and barrel wear in the extruder. The abrasive and adhesive wear on these two components caused by the choice of material and operations of the extruder will eventually wear them. As these two components wear, less material is conveyed per turn of the feedscrew because material is flowing backwards over the flights. This is most clearly indicated in the specific output (output/rpm) of a benchmark material. Over time, this value will reduce, indicating wear and loss of extruder efficiency. If this value has not been recorded, please contact us so we can check the original design and historical records of this line.
Q: How do I stop curling when processing asymmetric (nylon outside) barrier structures?
A: A nine-layer line to balance the structure by adding the nylon layer closer to the inside layer will fix this issue. A water bath annealing system would also address it.
Q: How can I eliminate carbon buildup at the die lip when running nylon?
A: Frequent cleaning of the die lip is necessary because polymers that process at lower temperatures are exposed to the high temperatures required for nylon. Lower both outer and inner lip temperatures if the process allows.
Q: How can I resolve poor gauge distribution?
A: First, ensure the die gap is even and the die lips are cleaned. Ensure die temperature are set correctly for the polymers being run. Ensure the air flow to the air ring is evenly distributed and bubble is properly seated in the air ring. Lastly, check that the air ring lips are cleaned.
Q: How can I resolve edge wrinkles or droopy edge?
A: To resolve edge wrinkles or droopy edge, check that collapsing frames are parallel with nip rollers, and then check the alignment of the die center line with the primary nip. It could also be that the collapsing angle is too wide, so try closing the collapsing frames, then check film thickness gauge distribution.
Q: How do I resolve bubble sag in the centre of the web?
A: When the bubble geometry is not correct, bubble sag occurs. To fix this, increase output to collapse film at a higher temperature before the nip.
If the bubble collapsing angle is too large, close the collapsing frame to decrease the collapsing angle. Lastly, it could be the heat transfer from collapsing rolls is much too high. Change your collapsing roller type to ones with lower heat transfer rate.
Q: How can I eliminate wrinkles in my film?
A: To eliminate wrinkles, first check gauge distribution on the film.
Next, verify that air ring cooling distribution is not impaired. Verify that bubble control is stable. If wrinkles are not in the MD or angular, check the alignment of idler rolls. If wrinkles are at the edges of the roll, check for misaligned collapsing frames or collapsed angle of bubble.
Q: What's the best method to eliminate blocking?
A: Add an anti-block additive to the inside layer. Next, increase external and internal bubble cooling, and/or decrease melt temperatures.
Q: How can I prevent gels?
A: If you have gels in an extruded product, it's important to know whether they originated in the incoming raw material or were created during extrusion. For instance, gels formed during polymerization are called P-gels. E-gels form during extrusion. Please contact us for more information on helping with this issue.